ABB RET670 Product Manual page 52

Transformer protection RET670 ANSI
Pre-configured
Product version: 1.2
Table 26. Restricted earth fault protection, low impedance REFPDIF (87N)
Function
Operate characteristic
Reset ratio
Base sensitivity function
Directional characteristic
Operate time, trip function
Reset time, trip function
Second harmonic blocking
52
Range or value
Adaptable
>95%
IBase
(4.0-100.0)% of
Fixed 180 degrees or ± 60 to ±
90 degrees
20 ms typically at 0 to 10 x IdMin
25 ms typically at 10 to 0 x IdMin
(5.0-100.0)% of fundamental
1MRK 504 118-BUS A
Accuracy
± 1.0% of I for I < I
n n
± 1.0% of I for I > I
n
-
± 1.0% of I
n
± 2.0 degree
-
-
± 2.0% of I n
r
ABB